Washington DC - Democratic Congresswoman Alexandria Ocasio-Cortez took to Instagram on Sunday to slam presidential candidate Dr. Jill Stein, claiming the Green Party nominee is "not serious."

"Y'all, this is a little spicy, but I have thoughts," AOC prefaced her answer to a question on Stein's presidential campaign.

"What I have a problem with is the fact that if you are running for president, you are the de facto leader of your party," she said. "You are the leader of your party, and if you run for years and years and years and years and years in a row and your party has not grown and you don't add city council seats and you don't add down-ballot candidates and you don't add state electeds, that's bad leadership."

"If you have been your party's nominee for 12 years in a row – four years ago and four years before that and four years before that – and you cannot grow your movement pretty much at all and can't pursue any successful strategy and all you do is show up once every four years to speak to people who are justifiably pissed off but you're just showing up once every four years to do that, you're not serious."

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"To me, it does not read as authentic. It reads as predatory."

Stein – who overwhelmingly won her party's nomination last month – ran for president in 2012 and 2016 but not in 2020.

AOC's allegations triggered angry responses from Green Party members and Stein herself.

"What's seriously predatory is pretending your candidate is 'working tirelessly for a ceasefire' when in reality they’re actively arming and funding genocide," the presidential contender and Harvard-educated physician clapped back on X.

Last month, AOC faced backlash for claiming during a Democratic National Convention speech that the Biden-Harris administration is "working tirelessly" for a ceasefire in Gaza – despite the White House rejecting demands for an arms embargo on Israel.

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Stein, by contrast, has made Palestinian liberation a central tenet of her presidential campaign – and even got arrested at a Gaza solidarity encampment at Washington University in St. Louis last April.

She and the Green Party are currently engaged in a grassroots-powered push to appear on November ballots nationwide, while at the same time fighting off Democratic legal challenges aimed at blocking their access.

"Democrats sue to kick us off ballots, hire operatives to infiltrate and sabotage us, lock us out of debates, fight ranked-choice voting, then act concerned that Greens have only won 1400 elections. So which party is authentic, and which is predatory?" Stein said in a separate X post.

Green Party members shot down accusations that Stein does not prioritize party building and testified to her personal efforts in boosting down-ballot candidates.

"Jill is quite literally the [most] dedicated activist and dedicated Green Party member I have ever met, no shade to the other amazing Greens out there," former Green Party candidate for Florida State House Samson LeBeau Kpadenou wrote on social media.